FR3081501A1 - SHUTTER FOR A TURBOREACTOR HAVING AN ABSENT RECTIFIER BLADE - Google Patents

Abstract

The invention relates to a repair shutter of a turbomachine having a fixed stator blade (38, 39) damaged or absent, this fixed blade (38, 39) damaged or missing leaving an opening (34) of a ferrule (31) for receiving an end of this fixed blade (38, 39). According to the invention, the shutter (48) arranged to close the free opening (34) being rigidly secured to this free opening (34).

Description

SHUTTER FOR TURBOREACTOR HAVING ABSENT RECTIFIER BLADE DESCRIPTION

TECHNICAL AREA

The invention relates to a double-flow turbomachine comprising a fan followed by a rectifier comprising fixed blades downstream of this fan with respect to the direction of flow of the flow, in which each fixed blade has an internal radial end engaged in a ferrule d 'an internal structure of a turbomachine.

PRIOR STATE OF THE ART

A double-flow turbomachine 1 such as that of FIG. 1, comprises an inlet sleeve 2 admitting air sucked in by a fan 3, before division into a central primary flow and a secondary flow surrounding the primary flow.

The primary flow then passes through a low pressure compressor 4 while the secondary flow is expelled rearward to generate a thrust. The primary flow then passes through a high pressure compressor 6, before reaching a combustion chamber 7 to be expanded in a high pressure turbine 8 then in a low pressure turbine 9, before being expelled.

Each turbine and each compressor has blades carried by a rotor 11 rotating around a longitudinal axis AX and carried by an internal structure of revolution 12 which surrounds it. This internal structure 12 is itself surrounded by an external structure of revolution 14 while being held thereon by radial arms 13.

The primary flow circulates in an annular space delimited internally by the rotor 11 and externally by the internal structure 12, and the secondary flow circulates in another annular space delimited internally by the internal structure and externally by the external structure 14.

The secondary flow having passed through the blower 3 is straightened by a series of fixed vanes 16, called OGV for Outlet Guide Vane, which are located downstream of the blower and upstream of the radial arms 13 carrying the internal structure, more clearly visible on Figure 2.

As illustrated in FIG. 3, each stationary blade 16 has a radially external end 17 provided with a platform 18 by which it is bolted to the structure, and an opposite radially internal end 19 which is engaged in a corresponding opening 21 of a shell 22 of the internal structure

12. Additionally, a seal 23 is interposed between the end 19 and the opening 21 to which this seal is rigidly secured by snap-fastening.

This seal 23 limits the risk of deterioration of the end 19 surrounded by the opening 21 under the effect of friction resulting from vibrations and other mechanical stresses occurring in service.

It may happen that a projectile such as a volatile sucked in by the engine, after having passed through the blower, causes the rupture of a rectifier blade, which leads for example to the situation in FIG. 4 in which the blade rectifier 16 is absent.

Such an anomaly detected during post-flight maintenance involves installing a replacement blade, so that the aircraft is authorized to take off. Indeed, as illustrated in FIG. 4, the absent righting vane leaves a free opening 24 through the ferrule, through which sand or the like can enter the internal structure 12, and degrade the equipment which it comprises.

In the example of FIG. 4, the internal structure 12 integrates, immediately downstream of the free opening 24, a control system 26 for opening relief valves 27 and its actuating cylinder 28, capable of being disabled by the entry of foreign bodies into the structure 12 such as sand.

The object of the invention is to provide a solution for repairing a turbomachine having a damaged rectifier vane, including when a replacement vane is not available.

STATEMENT OF THE INVENTION

To this end, the subject of the invention is a shutter intended to fill a free opening left empty in the absence of a fixed blade removed from a ferrule, this ferrule being configured to receive one end of this fixed blade, this shutter comprising fixing means in the opening for sealingly closing this opening.

With this solution, it is not necessary to replace the damaged or missing blade, it is enough to remove it and put in place the shutter, which ensures that impurities do not risk entering the internal structure of the motor and that the flow stream remains delimited in the absence of dawn. Since such an engine is designed and dimensioned to be able to operate with a missing rectifier blade, it can again be put into service for several flights, so that the airplane can be authorized to take off again.

The invention also relates to a shutter thus defined, in which the fixing means are of the snap type.

The invention also relates to a shutter thus defined, comprising a cover having an external face intended to cover the opening and an opposite internal face provided with a flange ensuring its snapping into the free opening.

The invention also relates to a shutter thus defined, obtained by additive manufacturing.

The invention also relates to a fixed turbomachine rectifier, comprising a ferrule provided with blade end receiving openings, the blades receiving openings being regularly distributed over the circumference of the ferrule, a blade being mounted in each opening. receiving end of blade except for an opening which is closed by a shutter thus defined.

The invention also relates to a rectifier thus defined, in which the shutter is arranged so as to be flush with the external face of two adjacent seals, each seal being disposed around one end of a blade received in an opening for receiving a blade tip.

The invention also relates to a rectifier thus defined, in which the shutter is located at a distance from each adjacent joint of between 0.4 and 1 mm.

The invention also relates to a turbomachine equipped with a rectifier thus defined.

The invention also relates to a method for repairing a turbomachine shell, the shell having a damaged or missing fixed stator blade, this damaged or absent fixed blade leaving an opening in the shell intended to receive one end of this fixed blade , this method comprising a step of closing the free opening with a shutter thus defined.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 already described is a longitudinal sectional view of a known turbomachine;

FIG. 2 already described is a view in longitudinal section of an upstream portion of a known turbomachine;

Figure 3 already described is a perspective view illustrating the mounting of a fixed vane of stator with a ferrule in a known turbomachine;

FIG. 4 already described is a view in longitudinal section of an upstream portion of a known turbomachine of which a fixed stator vane is absent;

Figure 5 is a perspective view of a ferrule equipped with a shutter closing an opening corresponding to a missing rectifier blade and located between two openings closed by two rectifier blades according to the invention;

Figure 6 is a perspective view of a ferrule having a free opening corresponding to an absent blade and located between two openings closed by two fixed blades of rectifiers with a shutter intended to close this free opening;

Figure 7 is a longitudinal sectional view of a ferrule portion equipped with a shutter according to the invention;

Figure 8 is a perspective view of a variant shutter according to the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

In FIG. 5, an internal ferrule 31 of a turbomachine rectifier intended to be located immediately downstream of a fan of this turbomachine, has an annular shape and has openings 32, 33, 34, 36, 37 passing through it. The ferrule 31 is part of an internal structure called inter-vein casing of the turbomachine interposed between the primary vein and the secondary vein.

These openings are regularly distributed around the longitudinal axis AX of the motor and each have an oblong shape oriented parallel to this axis AX. Each opening is intended to receive a radially internal end of a fixed stator vane. Two of these fixed vanes 38, 39 are shown in FIG. 5 with their respective radially internal ends 41, 42 each engaged in an opening 33, 36.

Each of these blades 38, 39 has its radially outer end, identified by 43, 44 provided with a platform for fixing to a peripheral casing, not shown, of the rectifier which they equip.

As can be seen in FIGS. 5 and 6, a seal 46 is interposed between the radially internal end of the blade 38 and the opening 33, this seal being snapped into the opening 33 and comprising a central opening traversed by the end 41 of the fixed blade 38. In the same way, another seal 47 of the same type is engaged in the opening 36 to receive the end 42 of the blade 39.

The opening 34 is free, that is to say that it is not crossed by a fixed vane. According to the invention a shutter 48 is provided to close this free opening 34 in order to prevent the entry of impurities such as sand or other particles present in the air flow sucked by the engine, and liable to pass through the shell. 31 towards the components mounted in the inter-vein casing that this ferrule delimits locally.

The shutter 48 is installed when a fixed vane of the rectifier has been damaged or destroyed and must therefore be removed for replacement. In the event that a replacement blade is not available during the ground maintenance operation, it suffices to install the shutter 48 to close the opening of the missing blade so as to allow the aircraft to fly again.

The shutter 48 is a part whose dimensions and shapes are similar to those of the seals 46 or 47, it has the same attachment system as these seals 46 and 47, for example by snap-fastening, and is advantageously manufactured in the same material.

This shutter 48 is thus simple to design and it can be made of resin by molding, or even by 3D printing. Its installation which does not involve any particular tool mainly requires dismantling a few fan blades to access the opening to be fitted, such an intervention can thus be carried out directly under the wing, that is to say without dismantling the engine. .

As visible in FIG. 7, the shutter 48 mainly comprises a cover 49 with a generally rectangular outline and of dimensions greater than that of the opening 34 to be closed. This cover 49 has an external face 51 which can be flat or curved according to the curve of the ferrule 31, and an internal face 52 from which extends a rim 53. This cover 49 with rectangular outline has a length substantially greater than that of the opening 34, and a width which corresponds substantially to the distance separating two consecutive openings of the shell 31, such as for example the openings 36 and 37.

This rim 53 extends to engage the internal face of the opening 34. In the example of the figures, it has a closed contour having a shape and external dimensions corresponding to those of the internal edge of the opening 34.

As visible in FIG. 6, this rim 53 is thus set back relative to the external contour of the cover 49, when viewed from the front relative to the internal face 52. This rim projects beyond the internal face 52 by extending perpendicularly to this one, as illustrated in figure 7.

More particularly, this rim 53 has in section, that is to say along a plane of section perpendicular to the cover 49, a form of rectilinear wall comprising at its free end a lug 54 which protrudes from its external face, for form a projection engaging with the internal face 56 delimiting the opening 34.

This lug 54 has a shape of spout, which projects outwardly from the rim 53 to ensure the locking of the shutter 48 in the opening 34 by snap-fastening. As an indication, this lug protrudes from the outer face of the rim 53 by a value of between 6 and 10 tenths of a millimeter, to come into engagement with the inner face 56 of the opening 34.

Once the opening 34 has been made accessible, the mounting of the shutter according to the invention thus mainly consists in placing it opposite this opening and in exerting pressure on its cover to snap it into this opening.

In general, the shutter 48 is arranged so as to be flush with the two adjacent seals 46 and 47, that is to say that its external face 51 is at the same distance from the axis AX as the external faces seals 46 and 47. Furthermore, the shutter 48 is located at a distance from each adjacent seal which is between 0.4 and 1 millimeter, which provides sufficient mounting clearance to facilitate nesting shutter, without generating significant aerodynamic loss.

In the example of FIGS. 1 to 7, the means for fixing the shutter are constituted by its flange 53, but other solutions can be envisaged, such as for example that illustrated in FIG. 8 comprising a cover 49 fitted at its internal face of folding legs 57, for example of metal. Each tab 57 extends perpendicularly projecting from the internal face, and has one end which can be folded outwards to extend beyond the periphery of the cover 49. These tabs 57 are uniformly distributed along the periphery of the cover. 49.

The installation of the shutter then consists in engaging it in the opening 34 to be closed, then in accessing the internal face of the ferrule to fold the ends of the tabs 57 outwards so that they block the shutter 48 on the opening thanks to the tabs 57 engaging on the internal face 56 of this opening.

Claims (10)

1. Shutter (48) intended to fill a free opening (34), left empty in the absence of a fixed vane (38, 39) removed from a ferrule (31), this ferrule (31) being configured to receive one end of this fixed blade (38, 39), this shutter (48) comprising fixing means (53) in the opening (34) to close this opening (34) in a sealed manner. 2. A shutter (48) according to claim 1, in which the fixing means (53) are of the snap type. 3. obturator (48) according to claim 2, comprising a cover (49) having an external face intended to cover the opening and an opposite internal face provided with a flange (53) ensuring its snap-fastening in the opening (34) . 4. Shutter according to one of claims 1 to 3, obtained by additive manufacturing. 5. Fixed turbomachine rectifier comprising a ferrule (31) provided with openings (33, 36) for receiving the blade tip (38, 39), the openings (33, 36) for receiving the blades being regularly distributed over the circumference of the ferrule (31), a blade being mounted in each opening (33, 36) for receiving the blade tip except for an opening (34) which is closed by a shutter (48) according to one of the claims 1 to 4. 6. Rectifier according to claim 5, wherein the shutter (48) is arranged so as to be flush with the external face of two adjacent seals (46, 47), each seal (46, 47) being disposed around one end d 'a blade (38, 39) received in an opening (33, 36) for receiving a blade tip (38, 39). 7. A rectifier according to claim 6, in which the shutter (48) is located at a distance from each adjacent joint (46, 47) of between 0.4 and 1 mm. 8. Turbomachine equipped with a rectifier according to one of 5 claims 5 to 7. 9. A method of repairing a ferrule (3) of a turbomachine, the ferrule (31) having a fixed rectifier blade (38, 39) damaged or absent, this fixed blade (38, 39) damaged or absent leaving a free opening (34) in the shell (31), this 10 method comprising a step of closing the opening (34) with a shutter according to one of claims 1 to 4.